It was in 1931 that the historian James Truslow Adams coined the phrase “the American dream.”

The American dream is not just a yearning for affluence, Adams said, but also for the chance to overcome barriers and social class, to become the best that we can be. Adams acknowledged that the United States didn’t fully live up to that ideal, but he argued that America came closer than anywhere else.

Adams was right at the time, and for decades. When my father, an eastern European refugee, reached France after World War II, he was determined to continue to the United States because it was less class bound, more meritocratic and offered more opportunity.

Yet today the American dream has derailed, partly because of growing inequality. Or maybe the American dream has just swapped citizenship, for now it is more likely to be found in Canada or Europe — and a central issue in this year’s political campaigns should be how to repatriate it.

A report last month in The New York Times by David Leonhardt and Kevin Quealy noted that the U.S. middle class is no longer the richest in the world, with Canada apparently pulling ahead in median after-tax income. Other countries in Europe are poised to overtake us as well.

In fact, the discrepancy is arguably even greater. Canadians receive essentially free health care, while Americans pay for part of their health care costs with after-tax dollars. Meanwhile, the U.S. worker toils, on average, 4.6 percent more hours than a Canadian worker, 21 percent more hours than a French worker and an astonishing 28 percent more hours than a German worker, according to data from the Organization for Economic Cooperation and Development.

Canadians and Europeans also live longer, on average, than Americans do. Their children are less likely to die than ours. U.S. women are twice as likely to die as a result of pregnancy or childbirth as Canadian women. And, while our universities are still the best in the world, children in other industrialized countries, on average, get a better education than ours. Most sobering of all: A recent OECD report found that for people ages 16-24, Americans ranked last among rich countries in numeracy and technological proficiency.

Economic mobility is tricky to measure, but several studies show that a child born in the bottom 20 percent economically is less likely to rise to the top in the U.S. than in Europe. A Danish child is twice as likely to rise as an American child.

When our futures are determined to a significant extent at birth, we’ve reverted to the feudalism that our ancestors fled.

“Equality of opportunity — the ‘American dream’ — has always been a cherished American ideal,” Joseph Stiglitz, the Nobel-winning economist at Columbia University, noted in a recent speech. “But data now show that this is a myth: America has become the advanced country not only with the highest level of inequality, but one of those with the least equality of opportunity.”

Consider that the U.S. economy has, overall, grown more quickly than France’s. But so much of the growth has gone to the top 1 percent that the bottom 99 percent of French people have done better than the bottom 99 percent of Americans.

Three data points:

— The top 1 percent in the United States now own assets worth more than those held by the entire bottom 90 percent.

— The six Wal-Mart heirs are worth as much as the bottom 41 percent of American households put together.

— The top six hedge fund managers and traders averaged more than $2 billion each in earnings last year, partly because of the egregious “carried interest” tax break.

President Barack Obama has been unable to get financing for universal prekindergarten; this year’s proposed federal budget for pre-K for all, so important to our nation’s future, would be a bit more than a single month’s earnings for those six tycoons.

Inequality has become a hot topic, propelling Bill de Blasio to become mayor of New York City, turning Sen. Elizabeth Warren into a star, and elevating economist Thomas Piketty into such a demigod that my teenage daughter asked me the other day for his 696-page tome. All this growing awareness is a hopeful sign, because there are policy steps that we could take that would create opportunity and dampen inequality.

We could stop subsidizing private jets and too-big-to-fail banks, and direct those funds to early education programs that help break the cycle of poverty. We can invest less in prisons and more in schools.

We can impose a financial transactions tax and use the proceeds to broaden jobs programs like the earned-income tax credit and career academies. And, as Alan S. Blinder of Princeton University has outlined, we can give companies tax credits for creating new jobs.